Selective ribbon-handling mechanism for carbon and fabric ribbons

ABSTRACT

A typewriter ribbon control for switching the operational mode of a typewriter between carbon ribbon, fabric ribbon and stencil operation, having selector means for selectively coupling and uncoupling a power arm to a fabric ribbon elevating mechanism and to a carbon ribbon elevating mechanism, and simultaneously selectively coupling and uncoupling a power drive mechanism to a fabric ribbon feed mechanism and a carbon ribbon feed mechanism.

United States Patent [72] Inventor Ronald ILMcLean Newington, Conn. {21] Appl. No. 808,516 [22] Filed Mar. 19, I969 [45] Patented Sept. 7, 1971 [73] Assignee Litton Business Systems, Inc.

New York, N.Y.

[54] SELECTIVE RIBBON-HANDLING MECHANISM FOR CARBON AND FABRIC RIBBONS 2 Claims, 8 Drawing Figs.

[52] US. Cl 197/156, 197/159 [51 Int. Cl B4lj 35/22, B41 j 35/10 [50] FieldoiSearch 197/151, 156,157, 158,159, 84

[56] References Cited UNITED STATES PATENTS 1,052,104 2/1913 Ursbruck 197/156 1,067,746 7/1913 Lawrence 197/156 2,919,008 12/1957 Whippo 197/157 3,104,750 9/1963 Canny et al 197/156 3,154,185 10/1964 Kamp 197/151 3,225,886 12/1965 Cetran et a1. 197/84 3,237,747 3/1966 Frechette et a1. 197/151 X 3,348,650 10/1967 Meinherz et a1. 197/151 Primary Examiner-Robert E. Pulfrey Assistant Examiner-Stephen C. Pellegrino Attorneys-Joseph R. Spalla and Cornelius P. Quinn ABSTRACT: A typewriter ribbon control for switching the operational mode of a typewriter between carbon ribbon, fabric ribbon and stencil operation, having selector means for selectively coupling and uncoupling a power arm to a fabric ribbon elevating mechanism and to a carbon ribbon elevating mechanism, and simultaneously selectively coupling and uncoupling a power drive mechanism to a fabric ribbon feed mechanism and a carbon ribbon feed mechanism.

PATENTEUSEP Hen 3,603A43 SHEET 1 [IF 4 STENCIL CARBON INVENTOR RONALD H. McLEAN ATTORNEY PATENTEDSEP TIBTI 3,603,443

SHEET 2 UF 4 INVENTOR RONALD H. McLEAN BY d M A TORNEY PATENTED SEP 7197:

SHEET 3 [1F 4 I08 Fig-6 INVENTOR RONALD H. Mc LEAN v A TORNEY PATENTEU SEP 7197! SHEET 4 UF Q INVENTOR ATTO NEY SELECTIVE RIBBON-HANDLING MECHANISM FOR CARBON AND FABRIC IIIEIIONS BACKGROUND OF THE INVENTION This invention relates to a typewriter and more particularly to an improved ribbon-handling mechanism in a typewriter for selectively switching the operational mode of a typewriter between carbon ribbon, fabric ribbon and stencil operation.

While it is possible with many of the typewriters of the prior art to operate in a carbon ribbon operational mode, a fabric ribbon operational mode, or a stencil operational mode, it is normally very inconvenient for the operator to accomplish changes between the carbon ribbon and the fabric ribbon operational modes. Since most typewriters of the prior art are equipped with only one vibrator it is normally necessary for the operator when switching between a carbon ribbon and a fabric ribbon operational mode, to manually remove one ribbon from the vibrator and replace it with another one and then make some adjustments to the ribbon feed drive mechanism.

Even with typewriters equipped with twin vibrators, in changing from one operational mode to another, there is often no provision made for disengaging drive to the ribbon feed mechanism of the previously selected ribbon. As a result, in such typewriters the fabric ribbon feed mechanism continues to operate even though the typewriter may be in a carbon ribbon or a stencil operational mode and the carbon ribbon feed mechanism continues to operate even when the typewriter is in a stencil or a fabric ribbon operational mode. In a machine which operates in such a manner, it is apparent that maximum utilization cannot be realized from either the fabric ribbon or the carbon ribbon.

It is also common for electric typewriters having twin vibrators to have separate and distinct power operated systems for actuating each of the vibrator mechanisms and separated and distinct power operated systems for operating each of the ribbon feed mechanisms. Thus, in many instances, there is a multiplicity of parts that lends to complexities in assembly and maintenance and increases the cost of the machine.

SUMMARY OF THE DISCLOSURE In the present invention, a power arm is selectively operable as determined by the position of a selector mechanism mounted for angular rotation on a typewriter frame to provide power to either a fabric ribbon vibrator mechanism or a carbon ribbon vibrator mechanism or neither of them, and a power drive mechanism is operable to power either a fabric ribbon feed mechanism or a carbon ribbon feed mechanism or neither of them. The selector mechanism has a plurality of camming surfaces for actuating cam followers which are adapted to selectively couple and uncouple the power arm to each of the ribbon vibrator mechanisms and the power drive mechanism to each of the ribbon feed mechanisms.

An object of the present invention is to provide a typewriter ribbon handling mechanism having a selector mechanism for shifting a typewriter from one operational mode to another.

Another object of the present invention is to provide a typewriter ribbon handling mechanism having a selector mechanism adapted to simultaneously coordinate the coupling and uncoupling of a power drive mechanism to ribbon feed mechanisms with the coupling and uncoupling of a power arm to ribbon vibrator mechanisms.

A further object of the present invention is to provide a power arm selectively operable to provide power to either a fabric ribbon vibrator mechanism or a carbon ribbon vibrator mechanism or neither of them, as determined by the position of a selector mechanism.

Still another object of the present invention is to provide a drive member selectively operable to power either a fabric ribbon feed mechanism or a carbon ribbon feed mechanism as determined by the position of a selector mechanism.

Other objects and advantages of the present invention will be apparent from the following description as illustrated in the accompanying drawing which discloses by way of example the principles of the invention and a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. I is a perspective view of a portion of an electric typewriter provided with the vibrators for carbon and for fabric ribbon.

FIG. 2 is a perspective view of a power arm in conjunction with a pair of drive arms for activating ribbon-elevating drive assemblies in accordance with the present invention.

FIG. 3 is a perspective view of a manually controlled ribbon selector wheel for coupling and uncoupling the power arm to the drive arms of carbon and fabric ribbon elevating drive assemblies and for simultaneously enabling and disabling respective carbon and fabric ribbon feed mechanism.

FIG. 4 is a side view of a portion of the manually controlled ribbon selector wheel shown in FIG. 3, illustrating the ends of a pair of cam follower arms in side by side relationship engaging cammed surfaces formed on a peripheral portion of the ribbon selector wheel.

FIG. 5 is a perspective view of a power drive mechanism for selective engagement with a carbon ribbon feed mechanism and a fabric ribbon feed mechanism.

FIG. 6 is a vertical sectional view of a drive member, and a trip wheel illustrated in FIG. 5, with a wrap spring adapted to couple the drive member to an extension of the typewriter power roll shaft.

FIG. 7 is an exploded view of a portion of the drive member and the trip wheel illustrating the relative size of the slots through which the wrap spring passes.

FIG. 8 is a developed view of a portion of the manually controlled ribbon selector wheel illustrating the shoulders of a slot in a transverse slide bar engaging cammed surfaces formed for controlling the relative lateral position of the drive member illustrated in FIGS. 57.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawing wherein like reference characters designate like or corresponding parts throughout the several views, there is illustrated in FIG. ll a type action, generally designated by the reference numeral 10, operable to power a U-bar lll adapted to selectively activate appropriate ribbon vibrator drive assemblies for elevating a fabric ribbon vibrator, generally designated by reference numeral 12, supporting a fabric ribbon FR, having three color tracks, black, blue and red, and a carbon ribbon vibrator, generally designated by the reference numeral 13, supporting a carbon ribbon CR.

As illustrated in FIG. I, the U-bar ill moves counterclockwise about a cross shaft M as will hereinafter appear, in response to type action operation initiated by the depression of alphanumeric key levers such as a key lever 15. The key lever I5 is fulcrumed on a cross-shaft I6 secured to the typewriter frame and is formed with a depending finger ll7 engaging the upper surface of a bent off shelf lib formed on the forward end of a rigid or nonflexible intermediate control lever 19 pivotally mounted on a cross shaft 210. An angularly rearwardly extending portion of lever I9 terminates with a tip 21 that normally underlies the lower edge of a tail 22 formed on a rockable cam 23. The cam 23 is pivotally mounted as at 23a on a sublever 24 of an actuating linkage, generally designated by the reference numeral 25, pivotally mounted on the cross-shaft Ml, and is biased in a counterclockwise direction by a spring 26. The counterclockwise limit of movement of the cam 23 relative to the sublever Z4 is determined by the engagement of a bent off ear 23hr on the cam 23 with an adjacent edge 2% of the sublever 2d. The actuating linkage 25 is articulately connected by a link 27 to a type bar 28 pivotally mounted on a segment wire 29 and is adapted to drive the type bar 28 from a normal position on a headrest 30 into printing contact with a typewriter platen 31, and at the same time, through a tail 32, extending from the sublever 24 and overly ing the U-bar 11, move the U-bar l1 counterclockwise.

In operation, the rockable cam 23 is displaced in a clockwise direction in response to the depression of the key lever so as to move into operative frictional driving engagement with a constantly counterclockwise rotating power roll 33, thereby initiating a powered printing stroke to the type bar 28 and counterclockwise movement of the U-bar 11. After typing impact, the type bar 28 and the sublever 24 are returned to their nonnal positions by means of a return spring 34, allowing the U-bar 11 to return to a normal clockwise position through the action of a biasing spring (not shown).

The fabric ribbon vibrator l2 and the carbon ribbon vibrator 13 are both positioned behind a type guide, generally designated by the reference numeral 35, which is fastened to a shiftable type bar segment 36 by a pair of screws 36a. The fabric ribbon vibrator 12 is formed with a common leg 126 which is bifurcated at its upper end. Each so formed upper leg (not visible) has a pair of prongs 12d formed to guide the fabric ribbon past the printing point. Each upper leg also has a bent over ear designated 12a and 12b in slideable engagement with the spaced vertical legs 35a and 35b of the type guide 35. The lower end of the common depending leg 12c is wrapped around and rockably mounted on a stud 37 formed on a lever 38 rigidly mounted on a shaft 39.

The carbon ribbon vibrator 13 has a pair of legs 40 joined intermediate their ends and each of whose upper ends are formed with three prongs 13a to guide the carbon ribbon CR past the printing point. The opening 40a between the upper end of legs 40 permits the side edges of the fabric ribbon vibrator leg 120 to guide the carbon ribbon vibrator. The lower ends of legs 40 are formed in a generally inverted U- shape with their terminal portions partially wrapped around and rockably mounted on studs 41 formed on a pair of levers 42 rigidly mounted on a vibrator-elevating rod 43. Carbon ribbon tension, applied by a carbon ribbon feed mechanism (not shown), avoids forward and rearward movement of the carbon ribbon vibrator 13.

As will hereinafter be described, when a ribbon control selector dial or wheel 45, shown in FIG. 3 and manually rotatable about a frame supported shaft 46, is set to a carbon ribbon operational mode, counterclockwise movement of the U-bar l1 occasioned by a type action 10 is transmitted through a carbon ribbon vibrator assembly, a portion of which is shown in FIG. 2 and generally designated by the reference numeral 44, to rotate the carbon ribbon vibrator elevating rod 43 (FIG. I Similarly, when the ribbon control selector wheel 45, shown in FIG. 3, is set to a fabric ribbon operational mode, counterclockwise movement of the U-bar l1 occasioned by a type action 10 is transmitted through a fabric ribbon vibrator drive assembly, shown in FIG. 2 and generally designated by the reference numeral 47 to rotate the fabric ribbon vibrator elevating rod 39.

With particular reference to FIG. 2 a drive pin 48 extends laterally from each side of a power arm 11a integral with and extending upwardly from the right side of the U-bar 11, into an elongated slot 49 in the forward end of a drive arm 50 of the fabric ribbon vibrator drive assembly 47 and into an elongated slot 51 formed in the forward end of a drive arm 52 of the carbon ribbon vibrator drive assembly 44.

Each of the elongated slots 49 and 51 has an upwardly extending detent 49a and 51a respectively, for receiving the drive pin 48 when their respective drive arm 50 and 52 is allowed to move downward to a drive position. A spring 53 connected between the forward end of drive arm 50 of the fabric ribbon vibrator assembly 47 and to a frame-mounted stud 54 biases the drive arm 50 downward to its drive position and a similarly connected spring 55 associated with drive arm 52 of the carbon ribbon vibrator drive assembly 44 biases the drive arm 52 downward to its drive position.

Normally as will hereinafter appear only one arm 50 and 52 is allowed in drive position. Thus with arm 50in drive position the drive pin 48 is in the detent 49a, and any counterclockwise movement of the U-bar l 1 will move the drive arm 50 forward to elevate the fabric ribbon vibrator 12 associated therewith. Similarly with the arm 52 in drive position drive pin 48 is in the detent 51a and any counterclockwise movement of the U- bar 11 will move drive arm 52 forward to elevate the carbon ribbon vibrator 13 associated therewith.

One or the other of drive arms 50 and 52 or neither (for stencilling) may be brought into operative drive association with the drive pin 48. This is accomplished by bellcranks, generally designated by the reference numerals 56 and 57 respectively having U-shaped bridge structures pivotally mounted adjacent each other on a frame mounted stud 58. The bell crank 56 has an arm 59 with an enlarged end portion 59a underlying a laterally bent off ear 60 formed on the fabric ribbon drive arm 50 and a depending cam follower arm 61 having an enlarged end portion 61a adapted to follow the surface of an associated inner cam track generally designated by the reference numeral 62 (FIG. 3), formed on a lower peripheral portion of the ribbon control selector wheel 45.

The profile of the cam track 62 as best seen in FIG. 4 has two steps A and B separated by an intermediate transition portion C. With the ribbon control selector wheel 45 in a fabric ribbon operational mode, step B of the cam track surface 62 engages the enlarged end portion 61:: of the cam follower arm 61 of the bellcrank 56, allowing the spring 53 to pull the forward end of the drive arm 50 downward to drive position with the detent 49a in engagement with the drive pin 48. Whenever the ribbon selector control wheel 45 is moved from a fabric ribbon operational mode setting to another setting, such as a carbon ribbon operational mode setting, as illustrated in FIGS. 2 and 3, the step A of cam track 62 is placed in contact with the enlarged end portion 61a of arm 61 of the bellcrank 56, pivoting the bell crank 56 counterclockwise as viewed in FIG. 2 and thereby raising the slotted end of the arm 50 and disengaging the detent 49a from pin 48 so that the drive pin 48 is free to reciprocate in the elongated slot 49.

Similarly, the bellcrank 57 has an arm 63 with an enlarged end portion 63a underlying a laterally bent-off ear 64 on the drive arm 52 and a depending cam follower arm 65 having an enlarged portion 65a for engaging the surface of a cam track generally designated by the reference numeral 66 formed on a peripheral portion of the ribbon control wheel 45 outwardly adjacent the cam surface 62 as viewed in FIG. 3 and separated from track 62 by a rib 45a.

The profile of the cam track 66 as best seen in FIG. 4 has two steps D and E separated by an intermediate transition portion F. With the ribbon control selector wheel 45 in a carbon ribbon operational mode, step D of the cam surface 66 engages the enlarged end portion 65a of arm 65 of the bell crank 57, allowing the spring 55 to urge the drive pin 48 to its drive position as illustrated in FIG. 2. Whenever the ribbon selector control wheel 45 is moved from a carbon ribbon operational mode setting to another setting i.e., stencil or fabric ribbon settings, movement of the cam 66 formed on the ribbon control selector wheel 45 places the step E into engagement with the enlarged end portion 650 of the arm 65 of the bellcrank 57, pivoting the bellcrank 57 counterclockwise as viewed in FIG. 2 and thereby raising the slotted end of the arm 52 and disengaging the detent 514 so that the drive pin 48 is free to reciprocate in the elongated slot 51.

The fabric ribbon vibrator drive assembly 47 has a toggle assembly, generally designated by a reference numeral 67, to rotate the vibrator-elevating rod 39 supporting the fabric rib bon vibrator 12 in response to movement of the drive arm 50. The toggle assembly 67 comprises two links 68 and 69 the common ends of which are pivotally joined together on a stud 70 fixed to the drive arm 50. The lower end of the toggle link 69 is pivotally mounted on a stud 73 fixed to a shiftable plate or support 74 and forming a fulcrum 73 for the toggle as sembly 67. The upper end of the toggle link 68 is pivotally connected to a ribbon lift crank formed by an arm 72 fixed to and extending outwardly from the vibrator elevating rod 39.

As best viewed in FIG. 2 the shiftable support 74 is pivotally mounted on a stud 75 mounted on the typewriter frame and is provided with a number of detent notches, H, I, J, K, L, for receiving an inverted V-shaped end portion 76 of a leaf spring 77 extending from an L-shaped frame mounted bracket 78. The leaf spring 77 acts as a detent and holds the shiftable support 74 and consequently the fulcrum 73 of the toggle assembly 67 in selected positions.

Detented positions H and I represent the condition when the wheel 45 is set to carbon ribbon and stencil positions respectively. Detented positions J, K and L are fabric ribbon positions to elevate ribbon FR to black, blue and red.

Thus, each of the positions J, K, L set the fulcrum 73 of the toggle assembly 67 to provide a prescribed degree of rotation of the vibrator-elevating rod 39 in response to movement of the drive arm 50 and consequently a prescribed stroke through which the fabric ribbon vibrator drive assembly 47, when actuated, elevates the fabric ribbon vibrator 12. The shiftable support 74 is adapted to be moved about the frame mounted stud 75 and its detent notches H, I, J, K and L moved into and out of engagement with the V-shaped detent 76 of the spring 77, by a link 79 articulately connecting the shiftable support 74 and as shown in FIG. 74 a depending arm 45b formed on the ribbon control wheel 45. Thus, by moving the ribbon control wheel 45 and thereby positioning different detent notches J, K or L of the shiftable support 74 into engage ment with the V-shaped detent 76 of the leaf spring 77, vibrator strokes of varying length necessary to place different color tracks of a fabric ribbon FR into the path of type bar 28 are provided in accordance with the different settings of the ribbon selector control wheel 45.

A complete description of the operation of the carbon ribbon vibrator drive assembly is set forth in copending application of Robert E. McGrath, Ser. No. 808,590 filed Mar. 19, 1969.

As illustrated in FIG. 5, power for feeding the carbon ribbon CR and the fabric ribbon FR is provided by a power drive mechanism generally designated by a reference numeral 80, mounted on a drive shaft 81 which is an extension of the continuously driven typewriter power roll 33. As illustrated in FIG. 6 the power drive mechanism 80 includes a wrap spring 82, normally held disengaged, laterally abutting a snapring 82a engaging a groove 82b formed in the drive shaft 81 and adapted when released to couple a ribbon drive member 88 to the drive shaft 81 on which it is rotatably mounted. The wrap spring 82 is adapted to wrap around and to be driven by the drive shaft 81 and in turn drive the ribbon drive member 88. The spring 82 is allowed to so couple the drive shaft 81. and the ribbon drive member 88 in response to release of a trip wheel 83, laterally fixed by a snapring 84 engaging a groove 84a in drive shaft 81 and rotatably mounted on the drive shaft 81. The trip wheel 83 also includes an annulus 85 extending laterally from one of its faces into an annular groove 86 in a face 87 of the ribbon drive member 88. The wrap spring 82 is placed around the drive shaft 81. One end 89 of the wrap spring 82 is bent radially outwardly of the coils and extends through a relatively wide arcuate slot 90 in an annular wall 91 extending axially from the ribbon drive member 88 which overlies the wrap Spring. The end 89 further extends through a narrow elongated slot 92 in the annulus 85 of the trip wheel 83 and into an arcuate slot 93 in the outer wall of the annular groove 86 in the face 87 of the ribbon drive member 88. The other end 89a of the wrap spring 82 is also bent radially outwardly and extends into a narrow elongated axial slot 94 in the inner annular wall 91 of the ribbon drive member 88 as best seen in FIG. 7 and into a wider slot 95 in the end of the annulus 85 of the trip wheel 83. With the trip wheel 83 arrested, slot 92 will prevent movement of end 89 of the spring and thereby prevent wrapping of the spring 82 around the drive shaft 81. The provision of the wider slot 90 in the annulus 91 of the ribbon drive member 88 permits relative circumferential movement between trip wheel 83 and the drive shaft 81 when the wheel 83 is permitted to rotate, thereby allowing the spring 82 to wrap and couple to shaft 81 be driven thereby, and in turn via end 8911 and slot 92 rotate ribbon drive to member 88.

As illustrated in FIG. 6, three lugs, spaced approximately 120 apart, two of which are shown, 96 and 97, protrude laterally from the other face of the trip wheel 83 for engagement with bent out bars respectively forming a summary and an offset secondary stop 99 and 100 extending from a pair of arms 101 and 102 respectively. The arms 101 and 102 are formed on a trip lever 103 pivotally mounted on a frame mounted stud 104. A rearward extending arm 11b on the left side of U-bar 11 as seen in FIG. 4 has a rod 105 extending laterally therefrom adapted to engage an arcuate slot 106 formed in the trip lever 103 and provided to allow the U-bar 1 1 to return to a normal position without moving the trip lever 103.

In response to pivotal movement of the Ubar 11 (in a clockwise direction as viewed in FIG. 5) the trip lever103 will be pivoted clockwise about the frame mounted stud 104 in opposition to the biasing action of a spring 107, releasing one of the lugs 96 protruding laterally from the face of the trip wheel 83 and allowing the wrap spring 82 to engage and couple shaft 81 and ribbon drive member 88. The trip wheel 83 and the rib bon drive member 88 will be driven approximately 120 when the next upstream lug 96 protruding from the face of the trip wheel 83 encounters the secondary stop 100 and thereby slot 92 will arrest and hold spring end 89 arrested, causing the wrap spring 82 to unwrap. Rotation of the ribbon drive member 88 by spring end 890 will be stopped when spring end 89a encounters the wall of slot 95. The return of the U-bar 11 to a normal position through the action of a biasing spring (not shown) after the completion of a type action 10, enables the trip lever 103 to pivot counterclockwise through the action of the biasing spring 107 thereby removing the secondary stop 100 from the path of the wheel lugs '96 with which it is engaged and immediately catching the same lug 96 with the primary stop 99.

Lateral movement of the trip wheel 83 to the right and left as viewed in FIG. 6 is prevented by the snapring 84 engaging the groove 84a in the drive shaft 81, and by the end 89 of wrap spring 82. The ribbon drive member 88 however may be selectively axially moved (left and right) to different positions relative to the drive shaft 81 as will hereinafter be described. In a far right position as shown in FIG. 5, a gear 108 formed on the periphery of the ribbon drive member 88 is adapted to engage a carbon ribbon take up spool gear 109 forming a part of a carbon ribbon feed mechanism (the remaining portion of which is not shown) and is thereby engaged to power the car bon ribbon feed mechanism in response to a type action 10. In a far left position a three lobed peripheral cam 110 formed with the ribbon drive member 88 to the left of the gear 108 is adapted to contact an enlarged end of a depending cam follower arm 111 pivoted as at 111a on the machine side frame SF of a fabric ribbon feed mechanism (the remaining portion of which is not shown) and is thereby operable to power the fabric ribbon feed mechanism 47 in response to a type action. In a position intermediate the far left and far right positions, a stencil position, the drive member 80 is disengaged from both the carbon ribbon feed mechanism and the fabric ribbon feed mechanism.

The ribbon drive member 88 is adapted to be moved left and right relative to the drive shaft 81 by a rearwardly extending lever 112 rockably mounted on the frame mounted stud 104. A pair of claw shaped fingers 113 and 113a formed on the rearwardly extending portion of the lever 112 engage a slotted collar 114 formed on the ribbon drive member 88. The forward end of the rockably mounted lever 112 has a U- shaped end 116 adapted to engage a notched end 117 of a transverse slide bar 118 extending transversely across the typewriter with an upright U-shaped slot 119 at one end forming shoulders 120 and 121 adapted to follow cam surfaces,

generally designated by a reference numeral 122 and 123 respectively having identical profiles and formed on opposite faces of the ribbon selector control wheel 45.

The profiles of cam surfaces 122 and 123 as best seen in FIG. 8 each have three steps X, Y and Z. Step X serves to position the transverse bar 118 to a far left position and the ribbon drive member 88 to its far right position as seen in FIG. with the gear 108 formed on the periphery of the ribbon drive member 88 in engagement with the carbon ribbon take up spool gear 109, step Z serves to position the transverse bar 118 to a far right position and the ribbon drive member 88 to its far left position with the surface of cam 110 contacting the cam follower arm 111, and step Y (stencil) serves to position the transverse bar 118 and the ribbon drive member 88 intermediate their far left and far right positions, and the ribbon drive member 88 out of engagement with any portion of a ribbon feed mechanism.

The operation of the selector mechanism may be summarized by the relative positions of the fabric ribbon vibrator drive arm 50, of the fabric ribbon vibrator assembly 47, the carbon ribbon vibrator drive arm 52 of the carbon ribbon vibrator assembly 44 and the ribbon drive member 88 for each of the typewriter operational modes.

I. Carbon Ribbon Operational Mode (as illustrated in the drawing) Fabric Ribbon Vibrator Assembly 47-The bellcrank 56 is maintained in a counterclockwise position by the cam follower arm 61 contacting the step A of the cam 62 thereby urging the drive arm 50 upwardly out of drive position. Thus the fabric ribbon vibrator drive assembly 47 is uncoupled from the power arm lla.

Carbon Ribbon Vibrator Assembly 44The cam follower arm 65 of the bellcrank 57 contacts the step D of the cam 66 thereby allowing the spring 55 to pull the drive arm 52 in a downward position; thus the carbon ribbon vibrator drive assembly 44 is coupled to the power arm 11a.

Ribbon Feed-The transverse bar 118 contacts the X steps of cams 122 and 123 positioning it in its far left position and thereby positioning the ribbon drive member 88 in engagement with the carbon ribbon feed mechanism.

[1. Stencil Operational Mode Fabric Ribbon Vibrator Assembly 47The bellcrank 56 is maintained in a counterclockwise position by the cam follower arm 61 contacting the step A of the cam 62 thereby urging the drive arm 50 upward; thus the fabric ribbon vibrator drive assembly 47 is uncoupled from the power arm 1 la.

Carbon Ribbon Vibrator Assembly 44The bellcrank 57 is maintained in a counterclockwise position by the cam follower arm 65 contacting the step E of the cam 66 thereby urging the drive arm 52 upward; thus the carbon ribbon vibrator drive assembly 44 is uncoupled from the carbon ribbon vibrator assembly.

Ribbon Feed-The transverse bar 118 contacts the Y step of the selector wheel cams 122 and 123 positioning it intermediate its far left and far right positions and thereby positioning the ribbon drive member 88 out of engagement with either a fabric ribbon feed mechanism or a carbon ribbon feed mechanism.

lll. Fabric Ribbon Operational Mode Fabric Ribbon Vibrator Assembly 47-The cam follower 61 of the bellcrank 56 contacts the step 8 of the cam 62 thereby allowing the spring 53 to pull the drive arm 50 in a downward position; thus the fabric ribbon vibrator drive assembly is coupled to the power arm 1 in.

Carbon Ribbon Vibrator Assembly 44The bellcrank 57 is maintained in a counterclockwise position by the cam follower arm 65 contacting the step E of the cam 66 thereby urging the drive the arm 52 upward; thus the carbon ribbon vibrator assembly 44 is uncoupled from the power arm 11a.

Ribbon Feed-The transverse bar 118 contacts the Z steps of the selector wheel cams 122 and 123 positioning it in its far right position and thereby positioning the ribbon drive member 88 in engagement with the fabric ribbon feed mechanism via follower 111.

Fabric Ribbon Color Track--The particular color setting of the ribbon selector control (black, blue or red) determines which detent notch J, K or L of the shiftable support 74 is engaged by the detent spring 76 and consequently the fulcrum 73 of the toggle assembly 67 and the track of the fabric ribbon FR which is positioned in front of the printing point in response to type action operation. With the ribbon control selector wheel 45 set to black fabric ribbon, the end 76 of the detent spring 77 engages the detent J of the shiftable support 74 and the fabric ribbon vibrator 12 is driven through a short stroke positioning the upper track of the fabric ribbon FR in a printing position in response to type action operation. With the ribbon control selector wheel 45 set to blue fabric ribbon the detent 76 of the leaf spring 77 engages the detent notch K of the shiftable support 74 and the fabric ribbon vibrator 12 is driven through an intermediate stroke positioning the intermediate track of the fabric ribbon FR in a printing position in response to type action operation. With the ribbon control wheel 45 set to a red fabric ribbon setting the detent 76 of the leaf 77 engages the detent notch L of the shiftable support 74 and the fabric ribbon vibrator 12 is driven through a long stroke positioning the lower track of the fabric ribbon FR in a printing position in response to type action operation. As hereinbefore noted the leaf spring detent 77 engages detent notches H a. l of the shiftable support 74 when the ribbon control selector wheel 45 is in a carbon ribbon and a stencil operational mode respectively and the fabric ribbon drive assembly 47 is uncoupled from the power arm 1 la.

The manually controlled ribbon selector control wheel 45 (illustrated in FIG. 3) is thus operable to shift the operational mode of a typewriter between a carbon ribbon operational mode, a fabric ribbon operational mode and a stencil operational mode, by selectively coupling and uncoupling the upwardly extending power arm 11a of the U-bar 11 with the carbon ribbon vibrator drive assembly 44 and with the fabric ribbon vibrator drive assembly 47, while simultaneously coupling and uncoupling ribbon drive member 88 to the carbon takeup spool gear 109 of the carbon ribbon feed mechanism and the cam follower arm 11 1 of the fabric ribbon feed mechanism.

The invention claimed is:

l. Ribbon selection and feeding control mechanism for a power-operated typewriter including a carbon ribbon vibrator, means including a first drive arm connected to elevate said carbon ribbon vibrator, a fabric ribbon vibrator, means including a second drive arm connected to elevate said fabric ribbon vibrator, a carbon ribbon feed mechanism, and a fabric ribbon feed mechanism,

a universal member operable incident to each typing action having a drive pin,

each of said first and second drive arms having an elongated slot in one end thereof for receiving said drive pin and a detent in the upper portion of each slot for engaging said drive pin,

springs urging said first and second drive arms toward engagement with said drive pin,

first and second cam follower means in contact with the ends of said first and second drive arms and movable to position said drive arms into and out of engagement with said drive pin thereby, incident to movement of said universal member, to elevate neither or one of said carbon ribbon and fabric ribbon vibrators,

drive means cyclically operable in response to movement of said universal member and selectively movable from a nondriving position to positions for driving engagement with said fabric ribbon and said carbon ribbon feed mechanisms,

third cam follower means selectively movable to position said drive means to one of its said positions,

and a single control wheel having first, second and third camming surfaces for acting on said first, second and third cam follower means.

2. Ribbon selection and feeding control mechanism as recited in claim I wherein said first and second camming surfaces are peripherally operative on associated cam followers llil bon takeup spool gear of said carbon ribbon feed mechanism, and a cam surface positionable to underlie and contact a cam follower arm of said fabric ribbon feed mechanism. 

1. Ribbon selection and feeding control mechanism for a poweroperated typewriter including a carbon ribbon vibrator, means including a first drive arm connected to elevate said carbon ribbon vibrator, a fabric ribbon vibrator, means including a second drive arm connected to elevate said fabric ribbon vibrator, a carbon ribbon feed mechanism, and a fabric ribbon feed mechanism, a universal member operable incident to each typing action having a drive pin, each of said first and second drive arms having an elongated slot in one end thereof for receiving said drive pin and a detent in the upper portion of each slot for engaging said drive pin, springs urging said first and second drive arms toward engagement with said drive pin, first and second cam follower means in contact with the ends of said first and second drive arms and movable to position said drive arms into and out of engagement with said drive pin thereby, incident to movement of said universal member, to elevate neither or one of said carbon ribbon and fabric ribbon vibrators, drive means cyclically operable in response to movement of said universal member and selectively movable from a nondriving position to positions for driving engagement with said fabric ribbon and said carbon ribbon feed mechanisms, third cam follower means selectively movable to position said drive means to one of its said positions, and a single control wheel having first, second and third camming surfaces for acting on said first, second and third cam follower means.
 2. Ribbon selection and feeding control mechanism as recited in claim 1 wherein said first and second camming surfaces are peripherally operative on associated cam followers and said third camming surface is axially operative on its associated cam follower means, and wherein said drive means is laterally shiftable by said third cam follower means and comprises a gear positionable for engagement with a carbon ribbon takeup spool gear of said carbon ribbon feed mechanism, and a cam surface positionable to underlie and contact a cam follower arm of said fabric ribbon feed mechanism. 